The present oil mist generators operating on a vortex principle enjoy a best combination of properties as compared to the known types of oil mist generators, namely, to the generators provided with a throat of a venturi. This results from the fact that a vortex-type oil mist generator enables a rotating flow of gas to be accelerated to high velocity and provides an increased magnitude of the differential in pressure across the oil delivery duct supplying the oil into the rotating flow of gas.
A vortex-type oil mist generator known to the prior art (cf., e.g., U.S. Pat. No. 3,515,676, U.S. Cl. 252-359) comprises a nozzle and an oil storage chamber provided with a baffle member located therein and arranged above the oil level. The nozzle is defined by a chamber having tangential gas delivery channels designed to create a rotating flow of gas, by an intermediate chamber suitable for supplying the oil into the rotating flow of gas, and by an oil mist outlet. The intermediate chamber has tangentially arranged inlet openings which are in communication with the oil storage chamber and are adapted for supplying the oil into the rotating flow of gas. In the oil storage chamber, the baffle member is located in the path of movement of the rotating flow of oil mist and serves to control the degree of oil mist dispersity.
When passing through the tangential gas delivery channels, the pressurized gas is caused to be swirled. The rotating flow of gas formed thereby creates, as it flows through the intermediate chamber, a suction area therein, which suction area causes an aspiration of the oil passing through the tangentially arranged openings of the intermediate chamber into the rotating flow of gas where it is then particalized, thus generating a rotating flow of oil mist. The generated oil mist as it leaves the nozzle outlet has a variable range of particle size. The baffle member tends to coalesce large-size oil particles and return them to the oil storage chamber, while large amounts of small-sized oil particles are useable to be directed to the machinery parts requiring lubrication.
However, the large-sized particles of the oil condensed on the baffle member form an oil film which has a tendency to draw a certain amount of small-sized particles thereinto, thus decreasing the oil mist density.
Furthermore, the known mist generator fails to adjustably control the oil mist dispersity when it is necessary to change the characteristics of the oil mist.
Also known is an oil mist generator of the vortex type (cf. U.S. Pat. No. 3,605,942, U.S. Cl. 184-626), which comprises an oil storage chamber, a vortex nozzle, and a screen member located in the path of movement of the rotating flow of oil mist. As in the case of the mist generator mentioned hereinabove, the nozzle comprises a combination of a chamber having tangential gas delivery channels adapted for creating a rotating flow of gas, an intermediate chamber supplying the oil into the rotating flow of gas, and an oil mist outlet. The intermediate chamber is provided with tangentially arranged inlets being in communication with the oil storage chamber and supplying the oil into the rotating flow of gas. The screen member is interposed in the path of movement of the gas rotating flow and is adjustable toward and away from the outlet of the nozzle.
In said generator, the nozzle functions in the same manner as in the generator described in the U.S. Pat. No. 3,515,676, U.S. Cl. 252-359. The oil mist, as it exits from the nozzle outlet, is formed by the oil particles which are variable in size. The large-sized particles impact against the screen member are broken down into small-sized particles, and then are directed to the machinery parts to be lubricated. The screen member is adjustable toward and away from the nozzle outlet to vary the size of oil particles. The size of the oil particles aerosolized in the gaseous carrier decreases as the screen member moves towards the nozzle outlet. Alternatively, when the screen member moves away from the nozzle outlet, the size of the particles increases. The screen member movable toward and away from the nozzle outlet effects the oil mist dispersity control.
However, when using the screen member, some large-sized oil particles settle thereon, thus forming an oil film interacting, in turn, with the rotating flow of oil mist moving past the screen. As a result, some of the small-sized particles are drawn into said oil film, which decreases the oil mist density.
The generated oil mist of decreased density requires an increased amount of pressurized gas for its transportation which leads to an excessive power consumption.